What is Causing This Man’s Groin Pain?
History
A 24-year-old soldier presented to the emergency department complaining of sharp, suprapubic pain with radiation along the inner thigh for the last 3 weeks. The pain began suddenly without precipitating trauma and had since ranged in intensity from 3 to 9 out of 10, sometimes inhibiting ambulation. On numerous occasions, he had sought healthcare at urgent care and primary care settings.
The patient’s past medical history included heroin addiction prior to joining the military at age 20. He had abstained from drug use while in the military until being prescribed opioids for a hand injury. Almost immediately after the injury, he began obtaining oxycodone tablets illegally to crush and inject for pain.
At the time of admission, he had sought treatment for addiction by a civilian physician with an oral combination of buprenorphine and naloxone. He reported his last intravenous drug use 6 weeks prior (Figure 1).
Physical Examination
Vital signs on admission were normal. He had palpable tenderness directly over the pubic symphysis, along each groin, and down his inner thighs. Pain was exacerbated by adduction of legs against resistance in the butterfly position. Also observed were several phlebotomy scars, or “tracks,” in each antecubital fossa.
He denied fever, dysuria, flank pain, and testicular pain.
Laboratory Tests
A CT of abdomen and pelvis revealed only nonspecific lymphadenopathy and splenomegaly. Previous laboratory work-up revealed a normal white blood cell count and negative monospot.
Laboratory findings were significant for a leukocytosis of 13.8 109/L (normal, 4 x 109/L to 10 x 109/L), an elevated platelet count of 512 109/L (normal, 150 x 109/L to 440 x 109/L), and an extremely high erythrocyte sedimentation rate at 117 mm/hr (normal, 0 mm/hr to 10 mm/hr).
An MRI was ordered (Figure 2).
(Answer and discussion on next page)
Answer: Pubic Symphysis Osteomyelitis
Treatment
An immediate MRI revealed diffuse bilateral marrow edema of the pubic rami with surrounding inflammatory changes suggestive of osteomyelitis. A MRI of the entire vertebral column for hematogenous seeding of infection was negative. A transthoracic echocardiogram for endocarditis was negative. Aspiration of the pubic symphysis to confirm the diagnosis and obtain cultures was performed by interventional radiology.
After an infectious disease consult, intravenous vancomycin and levofloxacin wereinitiated empirically to cover staphylococcus and streptococcus species andgram negative organisms. Culture from the aspiration grew pan-sensitive Pseudomonas aeruginosa. The patient responded appropriately and was discharged on a 6-week course of oral levofloxacin. He had no further complications and regained full function.
Discussion
Osteomyelitis of the pubic symphysis is a rare condition, with only 100 cases reported in the literature between1973 and 2010.1 Most pubic osteomyelitis is the result of seeding from pelvic trauma.1 The most common pathogen is staphylococcus aureus.1 Pseudomonas aeruginosa is the second most common cause of osteomyelitis at this site, occurring in 87% of cases attributed to intravenous drug abuse.1,2
References:
1. Ross JJ, Hu LT. Septic arthritis of the pubic symphysis: review of 100 cases. Medicine (Baltimore). 2003;82(5):340-345.
2. Magarian GJ, Reuler JB. Septic arthritis and osteomyelitis of the symphysis pubis (osteitis pubis) from intravenous drug use. West J Med. 1985;142:691-694.